<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>title</title>

</head>
<body>
<input type="button" value="小苏" id="btn"/>
<script src="common.js"></script>
<script>
  //为同一个元素绑定多个不同的事件,指向相同的事件处理函数
  my$("btn").onclick = f1;
  my$("btn").onmouseover = f1;
  my$("btn").onmouseout = f1;
  function f1(e) {
    switch (e.type) {
      case "click":
        alert("好帅哦");
        break;
      case "mouseover":
        this.style.backgroundColor = "red";
        break;
      case "mouseout":
        this.style.backgroundColor = "green";
        break;
    }
  }
  //  my$("btn").onmouseover=function (e) {
  //    console.log(e);
  //  };
</script>
</body>
</html>